1. Field of the Invention
The present invention relates generally to a method for detecting hearing impairment and, more particularly, to a hearing impairment detecting method and a device thereof.
2. Prior Art
There are many reasons for people to loose their ability to hear sound, which includes diseases, contagious diseases, medication induced impairment, exposed in noisy environment, aging and genetic factors accounting for people who lost their hearing capability. Hearing impairment may be divided to conductive hearing loss, sensorineural hearing loss (SNHL), and central hearing loss and mixed hearing loss based on the locations of the deformation.
The above SNHL is mainly caused by the damage of the inner ear or hearing nerve, generally infected by filterable virus, ototoxicity medications, or caused by aging and exposing in a noisy environment for a long period of time. SNHL occurs mostly in the inner ear and generally is associated with a recruitment effect which is that the patient can not hear clearly with low sounds and can not bear with loud sounds. These patients mostly have worse hearing performance in high frequency sounds than that of a low frequency sound. As a result, a lot of these kinds of patients can hear a low frequency vowel, but not a high frequency consonant. Clinically, these patients often complain that they can listen to, however, they do not understand the content.
People who suffer from hearing impairment can be improved by putting on the hearing aids. The fitting of a hearing aid usually counts on the doctor's clinical experiences and is determined according to the hearing test results to make the choice and adjustment of the hearing aid. Clinically, most hearing tests are subjective and have to be determined by the response of a patient to the sound stimulus. The objective hearing tests are few and usually require an expansive device such as the auditory evoked brainstem response (ABR). However, there is a well-known reflex—the audiovocal reflex, which is associated with both auditory and vocal systems. The reflex helps maintaining a phonation at a desired pitch and intensity. Loss or impairment of the reflex will affect the vocalization, especially a sustained stead-as-possible phonation. Because the audiovocal reflex is involuntary, this invention here is inspired by this idea and is to provide an OBJECTIVE method to test the hearing using the vocalization of a subject.